Context

• Scientists of the Zoological Survey of India have discovered seven species of water treaders, semi-aquatic insects that can walk or run on the surface of water.

Details

• The newly described species belong to the genus Mesovelia whose size ranges from 1.5 mm to 4.5 mm and are equipped with hydrophobic setae (bristles) on their legs. The combination of hydrophobic setae and water surface tension prevents them from sinking.
• The insects are pale green with silver-white wings with black veins on the basal half which make them stand out over the green mat of aquatic weeds. Among the new discoveries, Mesovelia andamana is from Andaman Islands, M. bispinosaand M. isiasi are from Meghalaya, M. occulta and M. tenuia from Tamil Nadu and M. brevia and M. dilatata live both in Meghalaya and Tamil Nadu.
• These bugs are hemimetabolous insects without having larval stage i.e., they go from egg to nymph to adult. They are found on freshwater bodies such as ponds, lakes, pools, streams, rocks with moss and sometimes on estuaries.
• These bugs serve as predators and scavengers (feed on midges, water fleas, feed on dead and dying mosquitoes), thereby removing organic waste and also providing a natural sanitation service. The females of Mesovelia are larger than males and dig several holes on plants and insert eggs in plant tissues with a specially adapted long serrated ovipositor (genital organ).
• There are 12 species of genus Mesovelia found in the country. While large water striders (Limnogonus, Aquarius, Cylindrostethus, Gerris, Ptilomera) are easily spotted upon the surface of water, the tiny Mesovelia are not as well-known.

Source;TH